1/*
 2 * net/tipc/node_subscr.c: TIPC "node down" subscription handling
 3 *
 4 * Copyright (c) 1995-2006, Ericsson AB
 5 * Copyright (c) 2005, 2010-2011, Wind River Systems
 6 * All rights reserved.
 7 *
 8 * Redistribution and use in source and binary forms, with or without
 9 * modification, are permitted provided that the following conditions are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the names of the copyright holders nor the names of its
17 *    contributors may be used to endorse or promote products derived from
18 *    this software without specific prior written permission.
19 *
20 * Alternatively, this software may be distributed under the terms of the
21 * GNU General Public License ("GPL") version 2 as published by the Free
22 * Software Foundation.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34 * POSSIBILITY OF SUCH DAMAGE.
35 */
36
37#include "core.h"
38#include "node_subscr.h"
39#include "node.h"
40
41/**
42 * tipc_nodesub_subscribe - create "node down" subscription for specified node
43 */
44void tipc_nodesub_subscribe(struct tipc_node_subscr *node_sub, u32 addr,
45			    void *usr_handle, net_ev_handler handle_down)
46{
47	if (in_own_node(addr)) {
48		node_sub->node = NULL;
49		return;
50	}
51
52	node_sub->node = tipc_node_find(addr);
53	if (!node_sub->node) {
54		pr_warn("Node subscription rejected, unknown node 0x%x\n",
55			addr);
56		return;
57	}
58	node_sub->handle_node_down = handle_down;
59	node_sub->usr_handle = usr_handle;
60
61	tipc_node_lock(node_sub->node);
62	list_add_tail(&node_sub->nodesub_list, &node_sub->node->nsub);
63	tipc_node_unlock(node_sub->node);
64}
65
66/**
67 * tipc_nodesub_unsubscribe - cancel "node down" subscription (if any)
68 */
69void tipc_nodesub_unsubscribe(struct tipc_node_subscr *node_sub)
70{
71	if (!node_sub->node)
72		return;
73
74	tipc_node_lock(node_sub->node);
75	list_del_init(&node_sub->nodesub_list);
76	tipc_node_unlock(node_sub->node);
77}
78
79/**
80 * tipc_nodesub_notify - notify subscribers that a node is unreachable
81 *
82 * Note: node is locked by caller
83 */
84void tipc_nodesub_notify(struct tipc_node *node)
85{
86	struct tipc_node_subscr *ns;
87
88	list_for_each_entry(ns, &node->nsub, nodesub_list) {
89		if (ns->handle_node_down) {
90			tipc_k_signal((Handler)ns->handle_node_down,
91				      (unsigned long)ns->usr_handle);
92			ns->handle_node_down = NULL;
93		}
94	}
95}